The immediate aim of this study is to use single crystal electron diffraction techniques to elucidate the three-dimensional structure of membrane phospholipids. In this research the structures of both diacyl phosphatides (including those with two saturated acyl chains as well as mixed acid phosphatides with a beta-unsaturated acyl chain) and single acid lysophosphatides will be determined. The conformational, valence and solid state packing information will be extrapolated to explain structural features of a biological membrane's amphiphatic matrix in relation to several dynamical membrane functions including the diffusion of electrolytes and non-electrolytes across this cell surface barrier. Attention will also be paid to membrane structural specificity resulting from the "profile" of a phosphatide mixture in a given membrane.